April 2011 was a remarkably warm and dry month. The total rainfall of 5.0 mm was only 10% of the Ross-on-Wye* average for April of 48.4 mm, and the average maximum temperature of 17.6 °C was 4.7 °C above the Ross average for April of 12.9 °C (about the same as for a normal early June).
* Ross-on-Wye is the nearest Met Office station for which long term averages (1971-2000) are available.
Day by day data for April are given below:-
MONTHLY CLIMATOLOGICAL SUMMARY for APR. 2011
NAME: Penallt
ELEV: 210 m LAT: 51° 46' 43" N LONG: 2° 41' 43" W
TEMPERATURE (°C), RAIN (mm), WIND SPEED (km/hr)
HEAT COOL AVG
MEAN DEG DEG WIND DOM
DAY TEMP HIGH TIME LOW TIME DAYS**DAYS RAIN SPEED HIGH TIME DIR
------------------------------------------------------------------------------------
1 11.9 15.1 13:30 10.5 7:30 6.4 0.0 1.2 4.2 29.0 15:30 SSE
2 11.8 16.2 15:30 6.3 23:30 6.6 0.0 0.0 2.4 20.9 3:00 SSE
3 8.8 13.4 16:00 5.7 00:00 9.5 0.0 0.8 1.0 14.5 12:00 SSE
4 7.8 11.9 15:00 3.3 5:00 10.5 0.0 0.0 2.3 20.9 16:30 SE
5 10.4 13.2 13:30 8.1 5:30 7.9 0.0 1.0 3.9 22.5 4:00 SE
6 13.9 19.5 15:00 10.1 21:30 4.6 0.1 0.0 2.1 17.7 13:30 SE
7 13.9 20.6 15:00 7.9 7:30 4.7 0.2 0.0 0.8 9.7 14:00 ENE
8 12.7 19.5 16:00 5.7 7:00 5.7 0.1 0.0 0.6 9.7 14:00 ENE
9 13.7 19.6 15:30 7.2 6:30 4.8 0.1 0.0 2.3 19.3 15:00 ENE
10 12.3 19.6 15:30 4.4 6:30 6.1 0.2 0.0 0.8 11.3 15:30 ENE
11 11.6 15.9 12:30 6.1 00:00 6.8 0.0 0.0 1.4 19.3 11:00 WSW
12 8.2 14.0 14:00 3.1 7:30 10.1 0.0 0.0 1.0 14.5 1:00 SW
13 6.7 8.9 13:30 4.3 2:00 11.7 0.0 1.8 1.4 19.3 14:30 SSE
14 9.9 14.1 16:30 6.6 1:30 8.4 0.0 0.0 1.1 9.7 4:30 SSE
15 11.0 15.6 16:00 7.3 7:00 7.3 0.0 0.0 0.6 16.1 17:00 SSE
16 11.1 16.5 15:00 4.7 6:30 7.3 0.0 0.0 0.2 6.4 14:00 SSE
17 12.7 19.4 14:30 6.5 6:30 5.7 0.1 0.0 1.0 11.3 23:00 ENE
18 12.2 17.1 14:00 6.9 6:30 6.1 0.0 0.2 1.4 20.9 15:00 ENE
19 13.2 21.2 15:30 4.9 6:00 5.7 0.4 0.0 0.8 9.7 15:00 ENE
20 14.6 21.7 17:00 7.9 4:00 4.3 0.6 0.0 1.0 11.3 14:00 ENE
21 16.0 23.2 16:30 9.2 6:00 3.4 1.1 0.0 1.3 14.5 15:00 ENE
22 15.9 23.4 15:30 7.7 6:30 3.1 0.7 0.0 1.0 14.5 14:30 SW
23 16.8 24.9 16:00 10.6 00:00 3.1 1.6 0.0 0.8 12.9 19:00 E
24 13.2 19.3 16:00 8.6 6:30 5.2 0.1 0.0 1.4 12.9 10:30 ENE
25 13.7 19.6 16:00 8.7 7:00 4.7 0.1 0.0 2.1 16.1 21:30 ENE
26 10.0 14.9 16:30 6.9 6:30 8.3 0.0 0.0 2.6 16.1 16:30 ENE
27 10.4 15.6 16:30 5.8 6:00 7.9 0.0 0.0 2.4 16.1 18:30 ENE
28 9.9 16.7 17:00 3.1 5:30 8.4 0.0 0.0 2.1 14.5 9:30 ENE
29 11.0 16.4 19:00 7.6 6:30 7.3 0.0 0.0 2.4 17.7 00:00 ENE
30 13.1 19.9 16:00 8.2 5:00 5.4 0.2 0.0 4.7 29.0 19:30 ENE
-------------------------------------------------------------------------------------
11.9 24.9 23 3.1 12 196.9 5.3 5.0 1.7 29.0 1 ENE
Max >= 32.0: 0
Max <= 0.0: 0
Min <= 0.0: 0
Min <= -18.0: 0
Max Rain: 1.80 ON 13/04/11
Days of Rain: 5 (> .2 mm) 0 (> 2 mm) 0 (> 20 mm)
Heat Base: 18.3 Cool Base: 18.3 Method: Integration
** Degree Days
Although degree-days are most commonly used in agriculture, they are also useful in building design and construction, and in fuel use evaluation. The construction industry uses heating degree-days to calculate the amount of heat necessary to keep a building, be it a house or a skyscraper, comfortable for occupation. Likewise, cooling degree-days are used to estimate the amount of heat that must be removed (through air-conditioning) to keep a structure comfortable. Heating and cooling degree-days are based on departures from a base temperature, typically 65ºF (18ºC).
One heating degree-day is the amount of heat required to keep a structure at 65ºF when the outside temperature remains one degree below the 65ºF threshold for 24 hours. One heating degree-day is also the amount of heat required to keep that structure at 65ºF when the temperature remains 24ºF below that 65º threshold for 1 hour.
Likewise, one cooling degree-day is the amount of cooling required to keep a structure at 65ºF when the outside temperature remains one degree above the 65ºF threshold for 24 hours. One cooling degree-day is also the amount of cooling required to keep that structure at 65ºF when the temperature remains 24ºF above that 65º threshold for 1 hour.
Depending on the calculation method, both heating and cooling degree-days can accumulate in the same day. Also, note that there are no negative degree-days. If the temperature remains below the threshold, there is no degree-day accumulation.